The present invention relates to alarm systems used to indicate and prevent the unauthorized entry into, the use of, the removal of components or possessions from, or harm to vehicles or the occupants of vehicles. Specifically, the present invention relates to an alarm system for use on tractor-trailers, or other heavy-duty vehicles, which, due to the nature of their ordinary use, suffer extraordinary physical punishment or regularly undergo dramatic climatic changes or both.
The theft of automobiles and of the components of automobiles is a common occurrence and represents one of the largest areas of criminal activity with one of the lowest incidents of perpetrator apprehension. Therefore, prevention and deterrenee are the two keys to automobile protection. As the incidence of automobile theft and vandalism and the concomitant costs to owners and insurers have increased, the installation of alarm systems which are triggered upon the opening of car doors, hoods, windows, or gas tanks, or upon the excessive motion caused by touching or otherwise shifting the vehicle from its motionless, parked position, has significantly deterred the theft of automobiles so equipped.
Alarms of this type have become common and are in widespread use on passenger automobiles and light trucks. Typically, alarms of this nature can be installed on any vehicle, including tractor-trailers. However, alarm systems of the type designed primarily for use on passenger vehicles are entirely unsuited for use on heavy-duty tractor-trailers.
Tractor-trailers are put through much more rigorous use than are typical passenger automobiles. Tractor-trailers are driven virtually non-stop, day after day, over enormous distances the likes of which are traversed by ordinary vehicles only infrequently. Because of this heavy use, the normal strain and wear on truck components and systems is much higher than that experienced by automobile components and systems. The constant vibration and jarring associated with driving a tractor-trailer quickly causes components and systems designed for normal automobiles to fail due to breakage, stress, dislocation or disconnection. Accordingly, it is desirable that tractor-trailer components and systems be fashioned from more durable materials and made heavier in weight in order to withstand the much higher average levels of stress and vibration. Further, the corrosive effect of weather and dirt are magnified in tractor-trailers as compared to typical automobiles. Tractor-trailers routinely travel between and through different climates. This constant rapid change in the elements and violent fluctuation of temperatures serves only to exacerbate the corrosive effect of water, dirt and road salt upon the internal and external components and systems of tractor-trailers. Again, typical automotive components and systems are simply not fashioned to withstand the physical punishment taken by the more ruggedly constructed tractor-trailer components and systems.
When alarm systems designed primarily for use on passenger vehicles are installed on a tractor-trailers, the systems generally fail within a year of installation in the more strenuous environment. Constant pounding and jarring works plugs, fittings, connections and even screws loose. Delicate circuit boards and wires easily corrode and short when subjected to constant intermittent periods of dampness and dryness. This corrosive effect is only heightened when combined with the expansion and contraction, as well as condensation, caused by the frequent rapid temperature changes which tractor-trailers encounter as they are driven through differing climes.
Additionally, some modern car alarm systems include motion detectors which trigger the alarm when the vehicle has been rocked. Motion detectors are unsuitable for tractor-trailer alarm systems because the large surface area of the tractor-trailer often acts as a sail, catching the wind and shaking the vehicle even when parked. Therefore, even relatively small gusts of wind have the potential to trigger the motion detector of a typical car alarm system if it is installed on a tractor-trailer, resulting in numerous, annoying false alarms.
Finally, the wiring used in automobile alarm systems is, to a great degree, incompatible for the same use in tractor-trailers. Many car alarm systems require that the system's wiring be substituted for portions of the wiring of the vehicle in which it is installed. On a tractor-trailer, such a substitution is not only useless, as the extreme environment would quickly cause the smaller gauge car alarm system wiring to fail, possibly disabling vital electrical systems of the tractor-trailer in the process, but may also void any manufacturer's warranty on the truck. Clearly an alarm system which voids the more valuable warranty of the vehicle itself is of little practical value to a tractor-trailer owner.
The acceptance and usage of car alarm systems on tractor-trailers has been greatly limited, largely as a result of the high initial purchase price, the high cost of installation, the incompatibility of the wiring used on car alarm systems with the heavier wiring used in tractor-trailers, and, most of all, because of the unreliability of car alarm systems when used in the much higher stress environment of the tractor-trailer.
Furthermore, the security needs of a tractor-trailer and its driver differ greatly from those of the typical automobile and its driver. Besides the typical protection against the theft of the vehicle or its radio, an alarm system for a tractor-trailer must provide protection worthy of a home, for to many tractor-trailer drivers, their cab is literally a second home. Tractor-trailer drivers frequently sleep for long periods of time inside their vehicles. During these times, the exhausted drivers themselves are at great personal risk from the criminals who would break into their cab. Also, in addition to the valuable cargo which he is hauling, the tractor-trailer driver typically has a greater number of valuable possessions in his cab than does the typical automobile driver. Tractor-trailer drivers furnish their cabs with all of the comforts of home, from expensive two-way radios to refrigerators, televisions and VCR's. The presence of these valuable items, plus the large sums of cash which tractor-trailer drivers frequently have on hand to pay for hundred-plus gallon fuel fill-ups and other expenses encountered on trips that may be over a week in duration, make the tractor-trailer and its driver a lucrative target for the professional thief. Therefore, it is imperative that an alarm system for use on a tractor-trailer be capable of being armed from both inside and outside of the cab.
Furthermore, even when the driver is not inside his vehicle, the tractor is frequently left with the engine running, particularly in cold weather. This practice is a necessity of truck driving and only adds to the ease with which a tractor-trailer and its valuable cargo may be stolen.
Finally, notwithstanding the aforementioned reasons for making tractor-trailers as burglar-proof as possible, the manufacturers of tractor-trailers have traditionally used a minimum number of different key patterns for the keys which both lock and start these expensive machines. In fact, it is highly likely that the key to one tractor-trailer will unlock and start a tractor-trailer of similar make and year. This means that a knowledgeable thief can easily obtain the key for almost any tractor-trailer, thereby effortlessly obtaining unauthorized entry and use of the vehicle.